Python | Dictionary key combinations

Sometimes, while working with Python dictionaries, we can have a problem in which we need to get all the possible pair combinations of dictionary pairs. This kind of applications can occur in data science domain. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using list comprehension + enumerate()
In this method, we just iterate the dictionary through list comprehension and construct the pairs of keys and insert in new list. The enumerate function is used to bind the key elements together by accessing the indices.

# Python3 code to demonstrate working of
# Dictionary key combinations
# Using list comprehension + enumerate()

# Initializing dict
test_dict = {'gfg' : 1, 'is' : 2, 'the' : 3, 'best' : 4}

# printing original dict
print("The original dict is : " + str(test_dict))

# Dictionary key combinations
# Using list comprehension + enumerate()
test_dict = list(test_dict)
res = [(x, y) for idx, x in enumerate(test_dict) for y in test_dict[idx + 1: ]]

# printing result
print("The dictionary key pair list is : " + str(res))

Output :

The original dict is : {'is': 2, 'the': 3, 'best': 4, 'gfg': 1}
The dictionary key pair list is : [('is', 'the'), ('is', 'best'), ('is', 'gfg'), ('the', 'best'), ('the', 'gfg'), ('best', 'gfg')]

Method #2 : Using itertools.combinations()
This task can be performed using the functionality of combinations(), which internally takes just the keys to form the element pairs.

# Python3 code to demonstrate working of
# Dictionary key combinations
# Using itertools.combinations()
import itertools

# Initializing dict
test_dict = {'gfg' : 1, 'is' : 2, 'the' : 3, 'best' : 4}

# printing original dict
print("The original dict is : " + str(test_dict))

# Dictionary key combinations
# Using itertools.combinations()
res = list(itertools.combinations(test_dict, 2))

# printing result
print("The dictionary key pair list is : " + str(res))

Output :

The original dict is : {'is': 2, 'the': 3, 'best': 4, 'gfg': 1}
The dictionary key pair list is : [('is', 'the'), ('is', 'best'), ('is', 'gfg'), ('the', 'best'), ('the', 'gfg'), ('best', 'gfg')]